WATER SUPPLY PLANNING
COMMITTEE
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ITEM: |
ACTION
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2. |
Consider Adoption of Policy that will
Address Monterey County General Plan Requirements for Carmel Valley Alluvial
Aquifer |
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Meeting Date: |
July 12, 2016 |
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From: |
Dave Stoldt, |
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General Manager |
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Prepared By: |
Dave
Stoldt |
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SUMMARY: At the May 24, 2016 meeting, the Committee considered the MPWMD policy and the Monterey County General Plan policy for approving discretionary permits to use water produced from the Carmel Valley Alluvial Aquifer (CVAA) for new commercial and residential development projects. The Committee asked staff to develop a recommendation about modifying the District’s current policy for Water Distribution System permits and permit amendments in light of the General Plan Policy. The key question that must be addressed is whether the Carmel River (and associated CVAA) can be described as a long-term sustainable water supply using the factors set out in the General Plan policy. Two of the key factors involved in determining whether the CVAA can be considered a long-term sustainable water supply include the following from Policy PS-3.2:
e. Cumulative impacts of existing and projected future demand for water from the source, and the ability to reverse trends contributing to an overdraft condition or otherwise affecting supply; and
f. Effects of additional extraction or diversion of water on the environment including on instream flows necessary to support riparian vegetation, wetlands, fish or other aquatic life, and the migration potential for steelhead, for the purpose of minimizing impacts on the environment and to those resources and species.
The Committee needs to determine two aspects of a proposed policy:
1) Is the policy to be implemented only for conversions of vacant or agricultural land to developed use, where there is a prior production history? Shall the policy only include multiple connection development – i.e. exempt single family home? Exempt less than 4 connections? Shall policy include conversions from single residence to multiple connections? And
2) What methodology shall be used to set a new production limit? Four options are provided to the Committee below:
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Option 1 |
Option 2 |
Option 3 |
Option 4 |
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Allow a WDS to continue to pump based on a 10-year historical average of prior pumping. (Current) |
Determine existing consumptive use on site (evaporation & transpiration) and set as new production limit (adjusted for new project’s consumptive use.) |
Establish new limit at 85% of existing consumptive use and “retire” 15% to the benefit of the river. |
Establish new limit at 75% of existing consumptive use and “retire” 15% to the benefit of the river, and 10% to the District Reserve for re-allocation to Public Benefit Projects. |
Here, District Reserve refers to the reserve referenced by District Rules 30A and 33B and Public Benefit Projects refers to projects determined by a jurisdiction to be in the public interest, and includes publicly-owned facilities, non-profits, and/or projects with benefits to the public as determined by the jurisdiction. Both definitions will likely need to be better described in an enacting ordinance.
STAFF RECOMMENDATION: Staff recommends a new production limit for a site in the CVAA be established as follows:
· Upon conversion from vacant or agricultural to single connection residential: Option 2
· Upon conversion from vacant or agricultural, or single connection residential, to 2 or 3 residential connections: Option 3
· Upon conversion from vacant or agricultural, or from less than 4 residential connections, to 4 or more connections or to non-residential: Option 4
Staff should be directed to bring an ordinance implementing the recommendation.
DISCUSSION: Combined production from Cal-Am and non-Cal-Am wells in the CVAA likely peaked in the late 1980s as a result of the 1987-91 drought. Although Cal-Am has been required to report daily production data to MPWMD, accurate methods to determine non-Cal-Am production were not put in place until the early 1990s (e.g., see Ordinances 48 and 56).
The chart below shows CVAA diversions for all diverters for the period from 1995 to 2015.[1] Total production from the aquifer did not drop off significantly until the issuance of Cease-and-Desist Order 2009-0060 by the State Water Resources Control Board and the adoption of a steeply tiered water rate structure for Cal-Am deliveries, also in 2009. Non-Cal-Am producers are not affected by either the CDO or Cal-Am rates and remained at nearly the same level (about 2,000 AFY) for the 1995-2015 period, showing that non-Cal-Am pumpers have not significantly contributed to a reversal of trends contributing to an overdraft condition or otherwise affecting supply, nor toward minimizing impacts on the environment and species.
Currently, most non-Cal-Am pumpers in the CVAA have riparian rights to divert flow. The SWRCB declined to evaluate riparian rights in Order 95-10, stating that there was not enough information provided by non-Cal-Am pumpers; however, MPWMD requires an evaluation and demonstration of riparian rights in order to process a WDS permit or amendment for wells in the CVAA. This is not a determination of a right, but is a basis for MPWMD to confirm that the permittee has a long–term right to divert flow.
Riparian pumpers generally return a variable portion of the applied water and a portion of indoor water use back into the aquifer (the latter amount through septic system return flow in areas not served by the Carmel Area Wastewater District). The amount of applied water returned depends on land use. For example, agricultural production may require a different volume of water per acre than either turf irrigation or domestic landscape irrigation. To reverse the trend in seasonal dewatering, a baseline amount of water use should be established and a reduction factor applied to the baseline. Staff recommends that project proponents be required to provide an analysis of the consumptive use of water on the property under existing conditions for a period of 10 years (note that the consumptive use amount will be less than the historical pumped amount). The consumptive use amount would become the baseline.
Staff recommends that the Committee consider applying a minimum of a 15% reduction to the baseline for any conversion greater than a single residential connection in order to continue reversing the trend of dewatering of the aquifer and reducing flows when steelhead are migrating through the river. This is consistent with District’s 1984 goal of a 15% reduction in demand by the year 2020[2] as shown in its 1984 Water Conservation Plan, as supported by the Board in Resolution 84-4. The 15% goal was also indicated on page VI-9 in the Water Allocation Program Final Environmental Report (SCH87030309) certified by the Board in 1990. The same 15% goal is highlighted in Rule 25.5 B and was applied to the City of Monterey’s public water credit for the El Estero irrigation conversion project and to the City of Pacific Grove’s local water project. A higher permanent retirement was undertaken in the Pebble Beach (52.5%) and Malpaso LLC (35%) water entitlements. The Sand City water entitlement applied approximately 31% to offset Cal-Am Carmel River pumping.
Option 4 presents a scenario whereby the District will receive a portion of the water for reallocation for Public Benefit Projects. The details of such an approach would need to be established in a future ordinance reestablishing an allocation to the District Reserve.
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